Effects of NPK source on the dry matter partitioning in cool season C3-cereals (wheat,rye, barley,and oats) at various growth stages

Dry matter (DM) partitioning into root, leaf, stem, shoot dry weight plant^?1 response in four cool season C₃-cereals viz. wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.) and oats (Avena sativa L.) was investigated at 30, 60 and 90 days after emergence (DAE) under eight nitrogen, phosphorus and potassium (NPK) sources: S₁ = 20-20-20, S₂ = 20-27-5, S₃ = 7-22-8, S₄ = 10-10-10-20S, S₅ = 11-15-11, S₆ = 31-11-11, S₇ = 24-8-16, and S₈ = 19-6-12 in pot experiment at Dryland Agriculture Institute, West Texas A&;M University, Canyon, Texas, USA during winter 2009-10. A considerable variation in DM partitioning into various plant parts was observed in the four crop species at different growth stages and NPK source. At 30 DAE, 27% of the total DM per plant (TDMPP) was partitioned into roots and 73% into shoots (19% stems + 54% leaf). Only16 % of the TDMPP was partitioned into roots and 84% into shoots (18 % stem + 66 % leaf) at 60 DAE. At 90 DAE, 29% of TDMPP was partitioned into roots and 71 % into shoots (33 % stems + 38 % leaf) at 90 DAE. Percent DM partitioning into stems ranked first (33%) at 90 DAE > at 30 DAE (19%) > at 60 DAE (18 %). With advancement in crops age, DM partitioning into various crop parts increased. The root DM plant^?1 (RDMPP) increased from 11.5–722 mg plant^?1; stem DM plant^?1 (STDMPP) from 8.3–889.0 mg plant^?1; leaf DM plant^?1 (LDMPP) from 23.1–1031.0 mg plant^?1; shoot DM plant^?1 (SHDMPP) from 31.3–1921 mg plant^?1, and TDMPP increased from 42.9–2693.0 mg plant^?1 at 30 and 90 DAE, respectively. Because of the higher N contents in S₇ (24:8:16) and S₆ (31:11:11) reduced the DM partitioning into various plants parts as well as TDMPP at all three growth stages. The adverse effects of S₆ and S₇ on DM partitioning was more on oats > rye > wheat > barley. The S₄ with 10:10:10 (NPK) and :20S was not toxic at 30 DAE, but at 60 and 90 DAE it became toxic that adversely affected the DM partitioning as well as TDMPP probably may be due its high sulfur (20%) content which lacking in other NPK sources. The DM partitioning to various parts of barley and wheat was more than oats and rye at different growth stages (barley > wheat > rye > oats). Since the DM portioning values were determined on the average of five plants in pot experiment under organic soil at field capacity; in case of field experiments more research is needed on various crop species/varieties under different environmental conditions particularly under moisture stress condition.     

Cool Season C3-Grasses (Wheat,Rye, Barley,and Oats) Differ in Shoot: Root Ratio When Applied With Different NPK Sources

Shoot:root (S:R) response in four winter C₃-grasses (cereals) viz. wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.) and oats (Avena sativa L.) was investigated under eight different NPK sources (S₁ = 20-20-20, S₂ = 20-27-5, S₃ = 7-22-8, S₄ = 10-10-10-20S, S₅ = 11-15-11, S₆ = 31-11-11, S₇ = 24-8-16, and S₈ = 19-6-12) in pot experiment at Dryland Agriculture Institute, West Texas A&M University, Canyon, Texas, USA during winter 2009–2010. The experiment was performed in completely randomized design (CRD) with three repeats. The objective of this experiment was to investigate whether the S:R of winter cereals differ or not when applied with different NPK sources. Considerable variations in the shoot: root was noticed in the four grasses at different growth stages, i.e., 30, 60 and 90 days after emergence (DAE) when applied with different NPK fertilizers sources. Wheat had the highest S:R of 3.4 at 30 days after emergence (DAE), barley at 60 DAE (6.5), while oats at 90 DAE (3.9). Among the NPK sources, crops had the highest S:R of 3.6, 6.2 and 3.7 when applied with S₃, S₂, and S₆ at 30, 60 and 90 DAE, respectively. Shoot to root ratio showed positive relationship with increase in shoot weight and negative relationship with increase in root weight. The NPK fertilizer S₆ (31: 11: 11), an acid loving fertilizer had negative effects on the shoot and root development of cool season cereals, but among these cereals under study, barley and oats roots were affected more than wheat and rye. It was concluded from this present study, that the four cool season cereals responded differently in terms of shoot: root to different NPK fertilizers at different growth stages.     

Specific Leaf Area and Leaf Nitrogen Concentration of Lantana in Response to Light Regime and Triazole Treatment

Abstract

The paclobutrazol (0, 50, 100, 200, and 500 mg L^?1) and triapenthenol (175, 350, 700, and 1400 mg L^?1) effects on specific leaf area (SLA) and leaf nitrogen (LN) concentration of Lantana camara L. (subsp. camara) under the shading levels 0%, 27%, and 66% were determined in glasshouse experiments. In most cases, increased concentrations of paclobutrazol and triapenthenol decreased SLA and increased LN of plants logarithmically at all shading levels. The SLA, at all concentrations examined, was generally increased with increased shading; LN showed an increase at 66% shading compared to 0% shading in the case of triapenthenol. The SLA reduction of paclobutrazol‐treated plants in relation to untreated plants of the same shading level was 18% to 37%; reduction was 49% to 73% for plants treated with triapenthenol at 0% shading, indicating a greater effect of triapenthenol on SLA reduction than paclobutrazol at previous shading.     

Cumulative Effect of Soil and Foliar Application of Nitrogen,Phosphorus, and Sulfur on Growth,Physico-Biochemical Parameters,Yield Attributes,and Fatty Acid Composition in Oil of Erucic Acid-Free Rapeseed-Mustard Genotypes

ABSTRACT

The feasibility of split (soil + foliar) applications of nitrogen (N) and phosphorus (P) and addition of a small quantity of sulfur (S) in the spray was tested for improving performance of rapeseed-mustard genotypes in a factorial randomized field experiment. Three genotypes (two erucic acid free, viz. Brassica napus L. cv. ‘Hyola PAC – 401’ and Brassica juncea L. Czern. and Coss. cv. ‘TERI (0E) M 21-Swarna’, and one best performing high yielding Brassica juncea L. cv. ‘Rohini’ as a check) were grown with four soil (B) plus foliar (F) applications of N, P, and S with uniform basal 30 kg potassium (K) ha^{? 1} (K₃₀), viz. (i) the optimum soil-applied treatment supplemented with the spray of deionized water (B_N90P30 + Fw) comprising control, (ii) B_N70P30 + F _N20, (iii) B_N70P28 + F_N20P2, and (iv) B_N70P28 + F_N20P2S2. Soil Plus foliar application of nutrients, particularly B_N70P28 + F_N20P2S2, improved their performance with respect to growth characteristics (shoot length plant^{? 1}, leaf number plant^{? 1}, area leaf^{? 1}, leaf area index, fresh weight plant^{? 1}, and dry weight plant^{? 1}), physico-biochemical parameters (net photosynthetic rate, stomatal conductance, carboxylation efficiency, water use efficiency, carbonic anhydrase activity, leaf NPK content, and N use efficiency), yield attributes (pod number plant^{? 1}, seed number pod^{? 1}, 1000-seed weight, seed yield ha^{? 1}, oil content, and oil yield ha^{? 1}), and fatty acid composition in oil of these genotypes. The cultivar ‘Hyola PAC-401’ performed best particularly with B_N70P28 + F_N20P2S2. The improvement in the response of genotypes to the split application of nutrients may be attributed to their ready availability through foliar application.     

Effects of Biozyme (Ascophyllum nodosum) Biostimulant on Growth and Development of Soybean [Glycine Max (L.) Merill]

Field experiment was conducted to investigate the effects of Biozyme^TM on soybean. Application of Biozyme granule and crop-plus spray with half of recommended nitrogen, phosphorus, and potassium (NPK) showed significant effects on all the growth and yield parameters of soybean. The greatest value for the number of trifoliate leaves (29.95 leaves plant^?1), leaf area (1818.21 cm2 plant^?1), leaf area index (5.946), total chlorophyll content (1.995 mg g^?1 leaf fresh mass), number of nodules (35.086 plants^?1), fresh and dry weight of nodules (0.664 and 0.1592 g plants^?1), dry weight of root (8.564 g plants^?1), pods plant^?1 (69.0), seeds pods^?1 (3.25), straw yield (3.122 t ha^?1), biological yield (6.349 t ha^?1), and grain yield (3.277 t ha^?1) was observed with Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK and were significantly greater than control values. Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK performed better compared to other treatments.     

EFFECT OF NITROGEN FERTILIZATION ON STAY-GREEN AND SENESCENT SORGHUM HYBRIDS IN SAND CULTURE

Nitrogen (N) is vital in the production of N containing compounds in cereal crops. Stay-greenness in sorghum [Sorghum bicolor (L.) Moench] is characterized by the plant's ability to retain water and chlorophyll content at maturity. A greenhouse experiment was conducted to investigate the effect of the genotypic variability between stay-green (BT × 643) and senescent (RT × 7000) hybrids for leaf senescence, dry matter partitioning and N partitioning under three N levels (0.45, 0.90, 1.80 g plant^?1). The stay-green hybrid had a higher percentage green leaf area at 120 DAE with a higher residual N in leaves. The chlorophyll meter (SPAD-502) values for the stay-green hybrid during anthesis (75 and 85 DAE) were higher compared to its senescent counterpart. The results indicated that the expression of stay-green phenotype in sorghum was contingent on a minimum N supply of 1.35 g plant^?1 and associated with greater N acquisition. Nitrogen use and uptake in the stay-green hybrid were higher.     

Integrated Nutrient Management Affects Fruit Yield of Sapota (Achras zapota L.) and Nutrient Availability in a Vertisol

ABSTRACT

We studied the effect of integrated nutrient management (INM) combinations on supplement of plant nutrient for quantitative and qualitative fruit production in sapota. Thus, 17 combinations of INM practices were evaluated on fruit yield of sapota and nutrient availability in a Vertisol of Chambal region, India. The results demonstrated that almost all treatment combinations comprised of recommended dose of fertilizer (RDF), i.e. 1,000:500:500 g NPK plant^?1 with application of organic and inorganic sources of nutrients had a significant effect on the fruit yield of sapota, soil microbial biomass, NPK content of leaf, fruit and soil over control (T₁). Among different treatments, application of 2/3rd part of RDF + 50 kg FYM + 250 g Azospirillum + 250 g Azotobacter plant^?1 (T₁₁) significantly enhanced the number of fruits plant^?1 (327.88), yield plant^?1 (29.03 kg) and yield ha^?1 (4.52 t). However, the soil microbial count of fungi (8.89 cfu g^?1 soil), bacteria (11.19 cfu g^?1 soil) and actinomycetes (5.60 cfu g^?1 soil) at fruit harvest was higher under the 2/3 of RDF +10 kg vermicompost + 250 g Azospirillum + 250 g Azotobacter plant^?1 (T₁₅). The leaf nitrogen content (N, 2.03%) was higher in T_15, while phosphorus (P, 0.28%) and potassium (K, 1.80%) content were higher in T₁₁. It is evident that treatment T₁₁ increased fruit yield by 32% in Sapota cv. Kalipatti compared to control. Therefore, combined application of nutrient sources proved not only beneficial for enhancing fruit yield of sapota but also sustaining soil health in Chambal region of south-eastern Rajasthan.     

Effects of Vermicompost and Vermiwash on Plant,Phenolic Content,and Anti-oxidant Activity of Mexican Pepperleaf (Piper auritum Kunth) Cultivated in Phosphate Rock Potting Media

The aim of this investigation was to determine the effect of vermicompost, vermiwash, and phosphate rock on plant, total phenols, flavonoids, and anti-oxidant activity in Piper auritum Kunth leaves. P. auritum plants were obtained from cuttings and were planted according to the Box-Behnken experimental design with three repetitions at the central point. The factors and levels were vermicompost (10, 20, and 30 g plant^?1), vermiwash (5, 10, and 15 mL plant^?1), and phosphate rock (1, 2, and 3 g plant^?1). Plant growth parameters (plant height, stem diameter, leaves number) and chlorophyll content were measured 1 month after treatment applications. Total phenols, total flavonoids, and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity was measured after 4 months. Vermicompost, vermiwash, and phosphate rock had no statistically significant effect on plant growth. Plant height, stem diameter, leaves number, chlorophyll, innermost number, fresh weight stem, fresh weight leaves, fresh weight root, dry weight stem, dry weight leaves, and dry weight root were not different among treatments. Total phenolic compounds were statistically affected for both vermiwash and phosphoric rock (p < 0.05) and the anti-oxidant activity decreased by vermicompost addition. The application of 15 mL plant^?1 vermiwash, 1 g phosphate rock, and 20 g vermicompost plant^?1 increased the total phenol content.     

Effect of sulphur on biochemical parameters of rapeseed (Brassica campestris L.) in grey terrace soil

An experiment was conducted to study the biochemical response of rapeseed (Brassica campestris L.) to sulphur (S) fertilization at grey terrace soil. There were five treatments: S₀ (control), S₁ (20 kg S ha^?1), S₂ (40 kg S ha^?1), S₃ (60 kg S ha^?1) and S₄ (80 kg S ha^?1). Chlorophyll content in the leaf was determined at 30, 40, 50 and 60 days after emergence (DAE). The biochemical properties were found responsive to S. The highest chlorophyll content of mustard leaves was found in 60 kg S ha^?1 at 50 DAE. The same treatment also showed the maximum N content in the leaves at 45 DAE. The highest oil content was recorded in 60 kg S ha^?1. Other chemical characters such as acid value, peroxide and saponification values were lowest in 60 kg S ha^?1 while iodine value was found highest in the same S level. Non-essential fatty acids such as palmitic, stearic and erucic acid were increased in the rapeseed with decrease in S level, whereas essential fatty acids were maximum in 60 kg S ha^?1. Therefore, 60 kg S ha^?1 can be recommended to produce quality rapeseed in grey terrace soil of Bangladesh.     

Effect of Nitrogen Application Timing on Yield Components,Fodder, Grain,and Oil Yields of Brassica Cultivars

The dual-purpose use of Brassica cultivars means cutting or grazing the crop as fodder and then letting it to re-grow and produce grain with little or no yield penalty. A field experiment was conducted in randomized complete block design with split plot arrangement with three replications. Three Brassica cultivars, three nitrogen application timing, and cutting treatments were included in the experiment. The findings indicated that Brassica cultivar Abasin-95 produced higher fresh and dry fodder yields, seeds pod^?1, seed, biological, and oil yields. However, NIFA Raya resulted in a higher number of pods and branches plant^?1. Likewise, fresh and dry fodder yields were higher with nitrogen (N) application all at sowing. Nitrogen applied in two splits resulted in a higher number of pods plant^?1 and grain yield. Cutting suppressed all parameters except 1000 grain weight. Uncut plots produced significantly higher branches plant^?1, pods plant^?1, seeds pod^?1, seed, biological, and oil yields than cut plots.     

Starch concentration and impact on specific leaf weight and element concentrations in potato leaves under varied carbon dioxide and temperature

Foliar concentrations of starch and major elements, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg), along with specific leaf weight (SLW) were determined in the potato (Solanum tuberosum L.) cvs ‘Denali’, ‘Norland’, and ‘Russet Burbank’ grown for 35 days under CO₂ concentrations of 500, 1,000, 1,500 and 2,000 μmol.mol^‐1 at both 16°C and 20°C air temperature. The starch concentration, pooled from the three cultivars, increased with increasing CO₂ concentration at both 16°C and 20°C and was consistently higher at 16°C than at 20°C. The SLW (g.m^‐2) was positively related to the foliar starch concentration on the basis of leaf area or dry weight. The concentrations of N, P, Ca, and Mg in leaves were negatively related to starch concentration under =14% starch on a dry weight basis. Above 14% starch, there was no significant relationship between element and starch concentrations. Similar patterns were seen when the SLW and element concentrations were expressed on a starch‐free basis. In contrast, the leaf concentration of K was not closely related to the starch concentration because the K concentration was similar at varied CO₂ levels. The results of this study indicate that the changes in SLW and concentrations of N, P, Ca, and Mg in potato leaves only partially resulted from the changed starch concentration.     

Assessing resource use in gerbera genotypes for precision nutrient use in protected condition

Abstract

The present study was conducted in the existing germplasm block of gerbera under protected condition at ICAR-IIHR, Bengaluru, India during 2017–2019 to obtain comprehensive information on biomass partitioning, nutrient uptake pattern and flower yields in different genotypes for precision use of critical inputs. The number of leaves (187.6–353.2 m^?2?yr^?1) and flower stalks (166.9–274.5 m^?2?yr^?1) varied significantly among genotypes. Specific leaf area (SLA) was similar among Balance, Stanza, Arka Aswha and Terra Kalina cultivars (0.150–0.156?cm² mg^?1). Strong positive influence of SLA on number of flower stalks was evident from the significant correlation (r = –0.774). Significant positive correlations among number of flower stalks and leaves, leaf area and SLA substantiate the flower yield pattern in gerbera. Optimum leaf number per plant was estimated at 18.6, while optimum range was quantified at 14.1 to 22.4. In gerbera genotypes, the partitioning of total aboveground dry biomass to leaves and flower stalks was 46–61% and 39–54%, respectively. The average nutrient removal was quantified at 32.8?g N, 7.3?g P, 78.7?g K, 24.7?g Ca and 4.1?g Mg m^?2?yr^?1 and the uptake of macronutrients was in the order of K?>?N > Ca > P?>?Mg. The order of micronutrient removal (g m^?2?yr^?1) was Fe (0.2), Zn (0.08), Mn (0.06) and Cu (0.03). The soil fertility status at uniform management was above optimum. It is clear that leaf number, biomass partitioning and nutrient removal pattern had direct impact on flower stalk yields of gerbera.     

Two years of a field study on sesame growth and yield,nutrient uptake by PGP bacteria application and capsule type

Abstract

A two-year field experiment was conducted to study PGP bacteria on growth and yield productivity of sesame. Factors were control, Nitroxin, Biophosphor, and an equal combination of biofertilizers along with sesame capsule type. 1000-seed weight and oil content increased in the second year, but, seed yield reduced (-12.6?g m²), which represented a negative relationship between seed weight and yield. The effect of year on No. of single and multi-cap node plant^?1 was reversed. Seed yield, chlorophyll, protein, and N increased in the multi-cap seed, whereas, 1000-seed weight and seed weight plant^?1 was decreased. Maximum yield and yield components were achieved in the second and first year, respectively, along with the multi-cap seed. Nitroxin, after the equal combination, was approximately showed the maximum enhancement of growth and yield productivity of sesame. The most seed yield (4261 k ha^?1) was performed in the first year, combined biofertilizers and multi-cap seed, whereas, the highest oil content was gained in the second year and single-cap that it was due to the higher N and P use efficiency in the first year. No. of node plant^?1 and capsule No. plant^?1 showed the most correlation with the other parameters. Seed yield was correlated with No. of node plant^?1 (r?=?0.925) and leaf dry weight (r?=?0.885). The N and P use efficiency had been higher in the first year, multi-cap, and equal combination. Nitrogen Use efficiency was higher compared to phosphorous. The uptake of N and P by sesame increased with the integrated application of different bacteria.     

EFFECTS OF LIGHT LEVEL,CO2 ENRICHMENT,AND CONCENTRATION OF NUTRIENT SOLUTION ON GROWTH,LEAF NUTRIENT CONTENT,AND CHLOROPHYLL FLUORESCENCE OF BOSTON FERN MICROCUTTINGS

ABSTRACT

Boston Fern (Nephrolepis exaltata Schott. “Rooseveltii”) is often propagated in vitro. Microcuttings grow slowly after transfer from in vitro to ex vitro conditions. The aim of this study was to accelerate growth and to improve quality of plantlets by optimization of mineral nutrition, irradiance and CO₂ concentration. Two irradiance levels (50 and 150 μmol m^?2 s^?1), two concentrations of CO₂ (350 and 1200 μmol mol^?1), and five concentrations of nutrient solution (electrical conductivity: EC 0.3, 0.7, 1.4, 2.1, and 2.8 mS cm^?1) were tested. Microcuttings grown at higher irradiance accumulated more leaf fresh and dry weights than microcuttings grown at low irradiance. The higher irradiance level enhanced leaf nitrogen (N), phosphorus (P), and potassium (K) content. Carbon dioxide enrichment enhanced dry weight accumulation and plant height, decreased N and increased K content of leaves. The highest fresh and dry weight of leaves was measured at EC 2.1–2.8 mS cm^?1. Leaf N, P, and K content increased with increasing concentration of nutrient solution, leaf calcium (Ca) and magnesium (Mg) concentrations decreased with increasing concentration of nutrient solution. Microcuttings grown under high level of irradiance and high EC had higher chlorophyll fluorescence (F _m , F _v /F _m , S _c ) values than those grown under low light and low EC. Quality of propagation material of Boston fern can be significantly enhanced with the best combination of PPFD, mineral nutrition and CO₂ enrichment.     

Evaluation of White yam (Dioscorea rotundata) genotypes for arbuscular mycorrhizal colonization,leaf nutrient concentrations and tuber yield under NPK fertilizer application

Yield decline in yam may not only be due to soil nutrient depletion but also to the activity of soil microflora. Arbuscular mycorrhizal (AM) symbiosis helps in plant nutrition but may be affected by the application of fertilizer. The effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizer rates on the AM colonization, leaf nutrient concentrations, and tuber yields of eleven genotypes of Dioscorea rotundata were investigated at Ibadan, Nigeria. The soil was ferric luvisol. Eleven genotypes were selected from the previously conducted screening of 75 genotypes of D. rotundata for fertilizer response. Four application rates: 0, 200, 400, and 600 kg ha^?1 of NPK 15-15-15 were applied in a split plot design with four replications. Fertilizer rate was the main plot and variety was the sub plot. Percentage AM colonization was significantly reduced at 600 kg ha^?1 but not at lower rates when compared to zero rate and it was negatively correlated with leaf N, P, and zinc (Zn) concentrations. Leaf N concentrations were significantly increased at 200 kg ha^?1 in five genotypes and at 600 kg ha^?1 in two genotypes compared to zero application. Leaf P and K concentrations were decreased with the application of fertilizer in most of the genotypes. The NPK fertilizer of 15-15-15 at the rate of 200–400 kg ha^?1 gave yield response in eight genotypes of D. rotundata, with minimal or no effect on their AM colonization when compared to zero application. Long term study on the effect of fertilizer application on AM symbiosis in yam is recommended.     

Effects of organic fertilizers on yam productivity and some soil properties of a nutrient-depleted tropical Alfisol

Field experiments were conducted at Owo, southwest Nigeria to select organic fertilizer treatments most suitable for sustaining high soil fertility and yam productivity on a nutrient-depleted tropical Alfisol. Eight organic fertilizer treatments were applied at 20 t ha^?1 with a reference treatment inorganic fertilizer (NPK 15–15–15) at 400 kg ha^?1 and natural soil fertility (control), laid out in a randomized complete block design with three replications. Results showed that organic fertilizers significantly increased (p = 0.05) tuber weight and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and organic C concentrations compared with the NSF (control). The oil palm bunch ash + poultry manure treatment increased tuber weight, vine length, number of leaves and leaf area of yam by 66, 25, 21 and 52%, respectively, compared with inorganic fertilizer (NPK) and 37, 22, 19 and 44%, respectively, compared with poultry manure alone. Sole or mixed forms of organic fertilizers showed significant improvement in soil physical conditions compared with IF (NPK) and NSF (control). Synergistic use of oil palm bunch ash + poultry manure at 10 t ha^?1 each was most effective for sustainable management of soils and for improving agronomic productivity of yam.     

Evaluating Inorganic Nitrogen and Rye-Crimson Clover Mixture Fertilization of Spring Broccoli and Lettuce by 15Nitrogen Tracing and Mass Balance

ABSTRACT

Broccoli (Brassica oleraceaL. var. italica) and lettuce (Latuca sativaL.) were grown under greenhouse conditions with nitrogen (N) from a cover crop mixture of rye (Secale cerealeL.) and crimson clover (Trifolium incarnatumL.) and ammonium nitrate (NH₄NO₃). Individual cover crop species were produced with non-enriched or enriched (5 atom % NH₄ ¹⁵NO₃) Hoagland Nutrient Solutions resulting in enriched rye [0.799% atom % ¹⁵N, 24:1 carbon (C):N ratio] and enriched clover (0.686% atom % ¹⁵N, 19:1 C:N ratio). Cover crops were applied as an equal mixture of rye and clover at 1884, 3768, and 5652 kg·ha^{? 1} dry weight to supply 26, 52, and 78 kg·ha^{? 1} N. Enriched materials were only applied at the 3768 kg·ha^{? 1} rate, either as enriched rye plus non-enriched clover or non-enriched rye plus enriched clover. Additional treatments consisted of an unfertilized control and three NH₄NO₃ fertilizer rates; 112, 224, and 336 kg·ha^{? 1} N for broccoli and 70, 140, and 210 kg·ha^{? 1} N for lettuce. Combination treatments were the standard cover crop rate (3768 kg·ha^{? 1}) plus the lowest N fertilizer rate for each vegetable. Cover crops did not increase yield of either broccoli or lettuce, and contributed only 17% of the N in broccoli and 15% of the N in lettuce. The majority of cover crop ¹⁵N remained in the soil: 54.8% and 81.3% of rye and clover N, respectively, after broccoli harvest; and 68.1% and 79.2% of rye and clover N, respectively, after lettuce harvest. Broccoli plant tissue recoveries were 8.0% of the rye and 11.0 % of the clover ¹⁵N; while lettuce plant tissue recoveries were 6.3% (rye) and 4.1% (clover). Broccoli yield could not be assessed due to lack of floret development, but dry matter accumulation was maximized at 224 kg·ha^{? 1}N. Lettuce yield and fertilizer N recovery efficiency (by mass balance) was maximized at 140 g·ha^{? 1} N.     

Effect of Mycorrhiza,Organic Sources,Lime, Secondary and Micro-nutrients on Soil Microbial Activities and Yield Performance of Yam Bean (Pachyrhizus erosus L.) in Alfisols

Effect of integrated use of mycorrhiza, lime, inorganic fertilizers, and organic manures on microbial activities and yield performance of yam bean (Pachyrhizus erosus L.) was studied for two consecutive kharif (rainy) seasons during 2013–14 and 2014–15 in an acid Alfisol. The experiment was laid out with 16 treatments consisting of graded doses of soil test–based nitrogen, phosphors, and potassium (NPK); lime; mycorrhiza; organic sources, that is, farmyard manure (FYM), vermicompost, and green manure; secondary magnesium sulfate (MgSO₄) and micronutrients zinc sulfate (ZnSO₄ and borax). Significantly highest mean tuber yield (29.61 t ha^?1) was recorded due to integrated application of lime + FYM + NPK + ZnSO₄. Graded doses of NPK showed a mean yield response of 65%, 134%, and 191% due to addition of 50%, 100%, and 150% of NPK over control, respectively. Inoculation of vesicular–arbuscular mycorrhiza (VAM) combined with NPK and FYM recorded a mean tuber yield of 25.14 t ha^?1. Highest mean dry matter (18.85%) was recorded due to application of 150% NPK, whereas highest starch content on fresh weight basis was recorded due to integrated use of lime + FYM + NPK + MgSO₄ (11.11%). Application of 150% NPK has recorded highest dehydrogenase activity (2.018 µg TPF h^?1 g^?1) and fluorescein diacetate hydrolysis assay (2.012 µg g^?1 h^?1). Fungal inoculation of VAM in combination with lime + FYM + NPK recorded highest acid and alkaline phosphatase activities (82.20 and 67.02 µg PNP g^?1 soil h^?1, respectively). Soil biological activities and phosphatase activities had highly significant relationship with tuber yield and biochemical constituents of yam bean. The study emphasized the conjunctive use of soil test–based inorganic fertilizers, lime, and organic manures to enhance the enzymatic activities and to realize higher crop yields of yam bean in acid Alfisols.     

Growth Patterns of Jojoba Male and Female Leaf Callus with Various Ammonium and Nitrate Sources

Abstract

Male and female leaf discs of Jojoba [Simmondsia chinensis (Link) Schneider] were cultured on Murashige and Skoog (MS) media supplemented with various nitrate:ammonium ratio and phytohormones concentrations. For the optimum callus growth, hormonal concentrations were remained equal for both male and female leaf tissues i.e., 0.4 mg L^?1 2,4‐dichlorophenoxyaceticacid, 1.25 mg L^?1 6‐benzyladenine and 0.5 mgL^?1 kinetin. However, a statistically significant difference was observed when Murashige and Skoog media was supplemented with an additional nitrogen source. In female leaf tissue, maximum fresh and dry weights were recorded in Murashige and Skoog media supplemented with an additional source of NO₃ ^?:NH₄ ⁺ (60 mM) whereas in male leaf tissue this addition was inhibitory. This study suggests that nitrogen requirement may be different for optimum callus growth in both male and female leaf tissues.     

Chlorophyll meter estimates leaf area‐based nitrogen concentration of rice

Abstract

The chlorophyll meter (SPAD‐502) can be used to diagnose the nitrogen (N) status of rice (Oryza sativa L) plants to determine the need for fertilizer‐N topdressing. However, accurate estimation of leaf N concentration on a dry weight basis (N_dw) by SPAD requires the adjustment of SPAD values for specific leaf weight (SLW). The objective of this study was to determine if SPAD estimates of leaf N concentration on a leaf area basis (Na) without correcting for SLW. SPAD values were measured from different genotypes at various growth stages with the chlorophyll meter. Leaf N concentration was determined by micro‐Kjeldahl procedure and expressed based on dry weight and leaf area. Specific leaf weight was calculated as the ratio of leaf dry weight to leaf area. At each growth stage, SPAD estimated Na better than Ndw, especially at the middle and later growth stages. When data for all stages were pooled, SPAD values also correlated with Na better than with Ndw (r value of 0.81 versus 0.43). This finding was also true across 80 genotypes. For estimation of N_a by SPAD, therefore, no adjustment of SPAD values for SLW is needed.